1. Field of the Invention
This invention relates to handle assemblies for manipulable surgical devices, and more particularly to release mechanisms within that handle assembly.
2. Prior Art
Laparoscopic surgery may be defined as minimally invasive surgery upon a patient, utilizing small or miniaturized medical devices by which body tissue is cut, removed or cauterized by small manipulable devices through small incisions or openings within the patient""s body.
One device needed for such surgery may be characterized as a grasper or dissector. Such a device may be utilized to grab, dissect, treat or move tissue out of the surgical situs where other tissue may be surgically treated.
There exists a need for a device which will permit ready manipulation of tissue of any particular size or thickness encountered which can be grasped and maintained or manipulated readily by a single hand of an operating surgeon, and which protects the surgeon from high voltage electricity when cauterizing a patient.
It is therefore an object of the present invention, to provide a grasper or dissector handle arrangement which improves upon the prior art.
It is a further object of the present invention, to provide a handle mechanism of a grasper or dissector device which permits maintaining or manipulating body tissue of any thickness encountered, by use of a simple release mechanism in the handle of the device.
It is yet a further object of the present invention, to provide a release mechanism which permits that medical grasper device to be multi-funtional, to maintain and/or to immediately release a grasping or treatment configuration to that medical device and to provide electrical high voltage insulation when cautery is applied to the handpiece device.
It is still yet a further object of the present invention to provide a handle release mechanism for a grasper device which is very simple to operate and inexpensive to manufacture so as to provide optimum economic conditions for the medical community.
The present invention relates to a handle assembly release mechanism for an elongated medical device such as a laparoscopic grasper or dissector. The handle assembly comprises an elongated frame element having a barrel housing at a first or uppermost end thereof, a cautery pin and elongated ring portion at a second or lowermost portion thereof for receipt of the operator""s fingers. The barrel housing is arranged to receive the proximal end of an elongated outer shaft of the grasper or dissector device. The elongated shaft of that grasper device has a distal end at which a pair of forceps are pivotably disposed. The forceps device at the distal end of the elongated shaft are opened and closed in a known manner by reciprocal movement of an inner shaft. The inner shaft has a proximal end that extends through the barrel housing and is in pivotable attachment with a movable handle member. The movable handle member pivots about a rear pivot pin in a rear pin opening in the frame of the fixed handle assembly.
A ratchet point is arranged at a mid-location of the elongated frame portion of the fixed handle assembly, and a biasing spring is arranged in that fixed handle assembly thereadjacent.
The release mechanism is arranged between the movable handle and the fixed handle. The release mechanism comprises a housing defined by a pair of elongated parallel plates. The elongated parallel plates have a bridging portion joining them therebetween. The release mechanism is attached at its rearmost end by the rear pin, to the rear pin hole in the movable handle. The release mechanism is pivotable about that rear pin.
A plurality of elongated arcuately-shaped toothed plates are disposed between the side members of the release mechanism. The plurality of arcuately shaped plates is comprised of a main toothed plate and several arcuately-shaped toothed sub-plates. The toothed plates have a first or forward end and a second or rear end. The main tooth plate has a rear pin hole at its rearward most end. The rear pin which extends through a release mechanism housing extends also through the rear pin hole of the main toothed plate. The forward end of the main toothed plate has a forward pin hole therethrough. A forward pin is disposed through the forward pin hole of the main toothed plate and is received in a pair of holes in the forward end of the release mechanism housing.
An elongated arcuately-shaped smooth plate is arranged adjacent the plurality of toothed elongated plates within the release mechanism housing. The elongated smooth plate has a first or forward end and a second or a rear end. The rear end of the arcuately-shaped smooth plate has a rear pin hole therethrough. The rear pin of the tooth plates and the release mechanism housing also passes through the rear end hole of the smooth plate.
The main toothed plate and the sub-plates with teeth, have an elongated slot extending in a generally forwardly to rearwardly direction.
The slot in the toothed plates has a first or forward end and a second or rearward end.
The smooth elongated plate has an elongated slot at its forwardmost end. The smooth plate is arranged to be pivotally juxtaposed adjacent the array of toothed plates. The smooth plate has its slot arranged at an angle with respect to the slot of the toothed plates. The slot in the smooth plate has a first end which is in alignment with the slot in the first or forward end of the toothed plates.
A pair of released buttons are arranged on each side of the pair of parallel plates defining the housing of the release mechanism. The release buttons are connected by a button pin extending therebetween. The button pin also extends through the slot in the toothed plate assembly as well as in the slot of the smooth plate.
In operation of the release mechanism of the present invention the operating surgeon would have fingers arranged through the fixed handle and the movable handle. Respective arcuate movement of the pivotable or movable handle towards the fixed handle would cause the inner shaft attached to the distalmost end of the movable handle to be pulled rearwardly and thus effect the closing of the forceps on the distalmost end of the grasper device. When the release button is in its rearwardmost position, with its connecting pin within the rearwardmost location of the slot within the release mechanism housing and also in the rearwardmost position in the slot of the toothed plate assembly and the slot in the smooth plate, movement of the movable handle with respect to the fixed handle is unhindered, thus permitting the surgeon to open and close the forceps of the medical device, at will. This is permitted by virtue of the smooth plate being pivoted upwardly about the rear pin, to a location where the upper edge of the smooth plate is disposed above the teeth in the toothed plate assembly. In that manner, the ratchet point in the framed portion of the fixed handle assembly is not permitted to engage the teeth within the toothed plate assembly.
When the movable handle member is pulled rearwardly and the release button arrangement is pushed forwardly in its slot within the release mechanism housing, the release button connecting pin is pushed forward in the slot of the toothed plate assembly as well as in the slot for the smooth plate. The smooth plate is thus cammed downwardly and pivoted about its rearwardmost pivot pin and pin hole due to the camming action of the release button pin in the slot therein. Thus the teeth in the main toothed plate and attached toothed sub-plates are exposed to the ratchet point in the fixed handle assembly, and those toothed plates are biased theretoward by the leap spring within the fixed handle assembly.
The attending surgeon may thus squeeze the movable handle towards the fixed handle thus ratcheting downwardly on the handle assembly. This permits the forceps to be closed in a stepwise manner. A body tissue may be grasped firmly within those forceps and held there by the ratchet point engaging any of the series of teeth within the elongated toothed plates.
Prompt release of the forceps from the tissue is effected by a downward pressure on the trigger-like bridging portion of the release mechanism housing. This downward pressure on the bridging portion of the released mechanism housing pushes the leaf spring downwardly and permits the movable handle to be displaced away from the fixed handle thus permitting the opening the forceps and permitting release of the body tissue from therebetween.
It is thus to be noted, that the unique release mechanism permits a wide range of angular openings of the forceps, to permit a locking thereat, thus enabling the operating physician to grasp almost any size body tissue thereby. The simple release of this mechanism, being effected by a trigger-like pull on the bridging portion of the release mechanism housing thus overides the engagement of the ratchet point with the teeth on the toothed plates, permitting a fast and responsive release of the tissue and actuating the grasper mechanism for a subsequent grasping operation.
The invention thus comprises a ratchet release mechanism for a medical device permitting a smooth and a stepped actuation of a grasper on a distal end of the medial device. The medical device has a fixed handle and a movable handle. The release mechanism comprises an elongated toothed plate arrangement supported in a release housing. An elongated smooth plate is arranged adjacent the toothed plate arrangement in the release housing. The release housing is pivotably supported between the handles to permit the handles to move in a stepped or a smooth manner to effect actuation of the grasper. The elongated plates are disposed about a common pivot pin. The release housing includes a slot with a pin extending therethrough, wherein movement of the pin effects arcuate displacement of the toothed plate arrangement with respect to the smooth plate. The smooth plate arrangement has a slot therein and the toothed plate arrangement has a slot therein, all of the slots having a commonly aligned forwardmost end. The fixed handle has a ratchet point thereon which is engageable with the toothed plate arrangement. The toothed plate arrangement is fixedly supported in the release housing. The smooth plate arrangement is pivotably supported in the release housing. The release housing is pivotably supported on the movable handle. A leaf spring is attached to the fixed handle to bias the toothed plate assembly in the release housing against the pivot point. The release housing has a bridging portion which is pressable to displace the toothed plate arrangement in the release housing out of engagement with the ratchet point, and thus permit smooth action of the grasper.
The invention also comprises a method of stepwise grasping and manipulating a body tissue in a laparoscopic procedure, by an elongated grasping device, said method comprising the steps of: pivoting a plurality of elongated, adjacently disposed arcuate members about a common pivot axis through their rear end thereof, each arcuate member supported in a housing, wherein at least one of the arcuate members has an upper edge with a plurality of teeth thereon, each of the arcuate members having a slot in a forward end thereof; engaging at least one of the arcuate members by a ratchet point in the grasping device to move a grasper jaw arrangement on a distal end of the grasper device to secure a tissue therein; and moving one of the arcuate members with respect to the remainder of the arcuate members to effect release of the arcuate members and unlocking of the grasper jaw arrangement and release of tissue therefrom. The method includes moving a pin transversely through the slots in the forward end of the plurality of arcuate members to effect the moving of the one of the arcuate members with respect to the remainder of the arcuate members thus effecting pivoting movement therebetween. At least one of the arcuate members has a smooth edge and the remainder of the plurality of arcuate members have teeth on a upper edge thereof. The slot in the arcuate member having a smooth upper edge thereon is arranged out of alignment with respect to the slots in the remainder of the arcuate members. The slot in the arcuate member having a smooth upper edge thereon has a rearmost slot portion arranged at an angle with respect to a forward slot portion thereof.